Vega Beast Bue Bue was the 74rth Monster, featured in Ep.68 of the Anime UFO Robot Grendizer; resembling a Demon, it was blue/black/purple, with longs claws for hands & talons for feet, horns on top of the head & had a long tail that with a tree tip end. Bue had wings on its arms for flight which were sharp enough to cut through any object as well blow enemies away with a guts of wing, and fired a Freezer beam from its mouth.

Maria in a conversation with Koji is reminded of her (little is any) memories of her childhood on Planet Fleed, elsewhere, hidden in a mountain in Hokkaido (actually, the Queen Spazer in disguise), Zuril, still reeling from his wounds, has mounted a new base of Operation and calls in a new Commander to assist him in the next mission, Kane, making the young commander his right hand man while he prepares the new base, using the upcoming snowstorm to clean up the region with the Beast Bue Bue; as it is launch, is photograph by Dambi who is visiting the area. Bue attacks a village by burying it in an avalanche, cutting the snow with its sharp wings and later destroys a JSDF Base, which was about to provide rescue.

Quick note: Kane is NOT liked by the lower ranks, due to plot related reasons, making him the main focus of the story – his ascension actually causing discontent and resentment among the troops.

As news of the weather in Hokkaido worsen, Hikaru expresses concern for her father's well being; Dambi discovers the Beast in his photo and tries to warn the center, but the line is cut off due to the storm forcing him to travel to the village in the storm and is later found by two men (Vega Soldiers) on a snow sleigh and take him to the village, where he makes his phone call warning the Space Center; the sleigh Driver overhears him and takes him outside at gun point, but both agents are tackled by Dambi who steal the sleigh (GTA: Snowstorm edition).

Team Grendizer flies to Hokkaido as Kane hunts Dambi with his me, the cowboy ends up falling into a cliff; However, Kane reprimanded in front of the Platoon by Zuril himself, after learning Team Grendizer was on its way; Zuril berates him as it was Losers like him Planet Fleed lost, revealing Kane is Fleedian. Kane then leads a large fleet of Midifos to amend for his mistake and attacks Team Grendizer (minus Hikaru, who broke from the group to search for her father, who she finds alive, hanging on a tree branch, delivering the Photo).

As Duke and the others shutdown the attackers, the fleet suddenly retreats, ignoring Kane as they were acting under Zuril's command, but the commander ignores Zuril and continues to fight against Grendizer and the others; Hikaru calls Duke and tells him of the direction of the new Base, but Maria continues to fight Kane in a one on one; getting shutdown, but he out maneuvers her, making her crash into the snow, but so does Kane due to mechanical damage to his vessel.

Duke and Koji find and attack the Mountain Base, Zuril sends Bue Bue to fight them; Grendizer and Double Spazer combine for aerial combat, but the Beast shoots them with its Freezer breath and the mecha crashes, but Duke fires Screw Punch cutting Bue's wings off, crashing into the snow; the Mecha then charges and jumps over Bue, the Monster tries to freeze Grendizer, but is disposes immediately with Double Harken. Having been defeated, Zuril orders to withdraw, leaving Kane behind.

Kane (with a broken shoulder) attempts to kill the Pilot of the Driller, only to (his shock) discover is Maria, who the latter recognizes the former immediately, memories of the two flashing back to her mind as kids just before the invasion. Kane then runs away, but falls due to his wound, Maria tries to talk to him but he points a gun at her, informing her he is now with Vega. Before any attempt to talk to him can be made, Kane (mounted by the pressure of his mistakes, defeat, abandonment &, most obvious of all, not wanting to shoot Maria) decides to shoot himself in the head, tears falling from his eyes as his life fades away. Maria is left to her grief of the many question unanswered about her past, crying over the body of her one time childhood friend; Duke promises to end the war to avoid any further loses of more loved ones.

Duke, Koji and Maria bury Kane and return home

P.S.: Definitively this guy is in my top tier list. Bue would fit perfectly as an UltraKaiju or Voltron .